JP2001527069A - Pyridine / picoline production method - Google Patents

Abstract

There is provided a high efficiency base synthesis process for shape selective production of pyridine and picoline products from ammonia and C1-5 carbonyl compounds. The process includes reacting ammonia and at least one C1-5 carbonyl reactant under suitable reaction conditions of temperature, pressure, and space velocity in the presence of a catalyst comprising a molecular sieve to produce a primary product comprising pyridine or picoline products and polyalkylpyridines or other higher molecular weight aromatic species, separating and collecting the pyridine or picoline products from the polyalkylpyridines or other higher molecular weight aromatic species, and circulating the polyalkylpyridines or other higher molecular weight aromatic species to the same or another catalyst under conversion conditions to yield additional pyridine or picoline products with substantially reduced amounts of polyalkylpyridines or other higher molecular weight aromatic species.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing pyridine and / or picoline.

[0002] Pyridine is an important intermediate in the production of pesticides, such as herbicides and pesticides, and pharmaceuticals, and is also useful as a solvent in the polymer and textile industries. Important derivatives of pyridine include, for example, nicotinic acid and nicotinamide (an essential vitamin for human health), chlorpheniramine (an antihistamine),
Includes cetylpyridinium (a fungicide and preservative), isoniazid (an important antitubercular agent) and Paraquat® (a herbicide).

[0003] Pyridines having one methyl group attached to the ring structure are called methylpyridines or picolines and include 2- or α-picoline, 3- or β-picoline and 4- or γ-picoline .

[0004] Pyridine and picolines are obtained as a by-product of the coal tar industry or coke production. However, only a small amount of pyridine is found in coal tar, and a method of obtaining pyridine by chemical synthesis is preferred. Chemical synthesis typically relies on a catalytic gas reaction (condensation) between ammonia (or amine) and a carbonyl compound such as an aldehyde or ketone. However, their chemical synthesis has traditionally suffered from the disadvantages of low yields and poor selectivity, as well as short operating cycles and catalyst life.

[0005] In the field of pyridine chemistry, the term "base synthesis" is well known and used, and the reaction of aldehydes and / or ketones with ammonia in the gas phase using a heterogeneous catalyst to form pyridine and its bases. Refers to a synthetic method for producing a base of an alkylated derivative. For example, the reaction of acetaldehyde with ammonia at 350-550 ° C. in the presence of a heterogeneous catalyst results in 2- and 4-methylpyridine (
α- and γ-picoline) are produced. As another example, acetaldehyde and formaldehyde react with ammonia to produce pyridine and 3-methylpyridine. Such pyridine synthesis methods are described, for example, in U.S. Pat.
No. 75,410 and U.S. Pat. No. 4,220,783 to Chang et al.

To produce pyridine and its alkyl derivatives, in the absence or presence of methanol and / or formaldehyde, in the presence of an amorphous silica-alumina complex containing various promoters, A reaction of ammonia with acetaldehyde or other specific molecular weight aldehydes has been performed. See, for example, U.S. Patent Nos. 2,807,618 and 3,946,020. The yield of the desired product using the latter catalyst is low. Also, as reported in Advancesin Catalysis, 18: 344 (1968), alkylpyridines were synthesized by passing gaseous acetaldehyde and ammonia through crystalline aluminosilicates NaX and H-mordenite. The initial conversion using these materials as catalysts is high, but the catalyst deactivation by coking is rapid, giving an industrially unattractive system characterized by poor catalyst stability.
Synthetic crystalline zeolites, such as ZSM-5, having an intermediate pore size of 1 to 12 as measured by the zeolite's Constraint Index have been found to provide industrially useful yields and product selectivities. Was issued. In the presence of a catalyst comprising a crystalline aluminosilicate zeolite ion exchanged with cadmium and having a silica to alumina ratio of at least 12 and a constraint index in the range of 1 to 12, ammonia and 2 to 4 carbon atoms U.S. Pat. No. 4,220,783 which teaches the synthesis of pyridines and alkylpyridines by reacting an aldehyde with No. is a pioneer in this discovery.

[0007] The use of a ZSM-5 catalyst component in a fluidized or moving bed reactor is taught in US Patent No. 4,675,410. U.S. Pat.No. 4,886,179 discloses pyridine by reaction of ammonia with a carbonyl compound, preferably with added hydrogen, on a catalyst containing a crystalline aluminosilicate zeolite ion-exchanged with a Group VIII metal of the periodic table. Are taught. The crystalline aluminosilicate zeolite has a constraint ratio of silica to alumina of at least 15, preferably 30 to 200, and a constraint index of 4 to 12, for example ZSM-5, which comprises Provides a high and selective yield.

[0008] US Pat. No. 5,013,843 discloses a tertiary aldehyde to a binary mixture of aldehydes and / or ketones which is used to produce a mixture of pyridine and an alkyl-substituted pyridine in a large scale continuous process. Or the addition of ketones is taught. In a preferred system, propionaldehyde is added to a binary mixture of acetaldehyde and formaldehyde to produce β-pyridine and pyridine. The catalyst for this process is a crystalline aluminosilicate zeolite in acidic form, having a constraint index of 1 to 12, for example ZSM-5.

However, despite recent advances, the methods that exist for producing pyridine and picoline have poor selectivity for the desired pyridines and alkylpyridines, making them unacceptable from an industrial point of view. The disadvantage is that Accordingly, it is an object of the present invention to provide an improved process for the synthesis of pyridine and picoline which provides the desired product in high yield and purity in a cost- and time-efficient manner.

Accordingly, the present invention provides: (a) reacting a reactant feed stream comprising ammonia and at least one C _1-5 carbonyl reactant in the presence of a molecular sieve catalyst to produce a pyridine or picoline product and a polyalkylpyridine Producing a primary product stream containing: (b) isolating from the primary product stream a product fraction containing a pyridine or picoline product and a polyalkylpyridine fraction containing polyalkylpyridines And (c) contacting the polyalkylpyridine fraction with a molecular sieve catalyst to produce a pyridine or picoline product-containing secondary product stream.

The process of the present invention substantially reduces the net yield of polyalkylpyridine or higher molecular weight aromatic hydrocarbon species and increases the yield of the desired pyridine and picoline products. Preferably, the net amount of polyalkylpyridine or higher molecular weight aromatic hydrocarbon species in the product fraction and in the secondary product stream together is less than 5%, more preferably 2% by weight of the total product yield Is less than.

Optionally, the conversion step (c) comprises recycling the polyalkylpyridine fraction to the catalyst used in the reaction step (a) and subjecting the contacting step (c) under the same reaction conditions as the reaction step (a). Do.

The present invention provides a “base synthesis” route to the formation of pyridine or alkylpyridine derivatives in which the carbonyl compound initially reacts with ammonia in the gas phase using a heterogeneous molecular sieve catalyst. The product of the base synthesis reaction is separated from the recovered pyridine and / or
Or separating into a picoline fraction and a polyalkylpyridine fraction, contacting the polyalkylpyridine fraction with a molecular sieve catalyst to produce additional pyridine and / or picoline products.

The carbonyl reactant used in the base synthesis reaction is a hydrocarbon compound having 1 to 5 carbon atoms and at least one carbonyl moiety. The carbonyl reactant involved in the catalytic reactions described herein can be formaldehyde, an aldehyde having 2 to 4 carbon atoms, a ketone having 3 to 5 carbon atoms, or a mixture thereof. Representative reactant aldehydes include acetoaldehyde, propionaldehyde, acrolein, butyraldehyde, and crotonaldehyde. Representative reactant ketones include acetone, methyl ethyl ketone, diethyl ketone and methyl propyl ketone. The carbonyl reactant may be present as a solution in water, for example as formalin, a formaldehyde solution in water, with a small amount of methanol to aid solubility.

[0015] The carbonyl reactant may include a mixture of two or more carbonyl compounds. When a mixture is used, each carbonyl component in the mixture is preferably present in a predetermined amount relative to the other carbonyl components. For example, if at least one of the carbonyl reactants is a mixture of formaldehyde and acetoaldehyde, the two components are present in a formaldehyde / acetaldehyde molar ratio of preferably 0.2 to 1.0, more preferably 0.4 to 0.8. I do. Alternatively, a mixture of acetoaldehyde and acrolein typically has a molar ratio of acetoaldehyde / acrolein of 0.7 to 1.25. Other mixtures of carbonyl reactants can be similarly formulated to selectively control the products of base synthesis. Preferably, the carbonyl reactant comprises a mixture of formaldehyde and acetaldehyde, and the primary products of the base synthesis reaction are pyridine and β-picoline.

The molar ratio of ammonia to carbonyl reactant (NH ₃ / CO) in the reaction mixture used is generally between 0.5 and 30, preferably between 0.5 and 10, more preferably between 1 and 5.

If desired, hydrogen gas (H ₂ ) can be added to the reaction, for example, H ₂ / H in a molar ratio of 0 (when no hydrogen is added) to 5.0, preferably 0.1 to 1.0. It may be added at the rate of the carbonylation reactant (H ₂ / CO).

The reaction conditions for conducting the base synthesis reaction between ammonia and at least one carbonyl compound include: (a) a temperature of 285 to 600 ° C., preferably 340 to 550 ° C .; (b) 20 to 2,000 kPa (0.2 to 20 atm), preferably 80 to 1,000 kPa (0.8 to 20 atm)
10 atmospheres) and (c) a gas hourly space velocity (GHSV) of 200 to 20,000 h ^-1 , preferably 300 to 5,000 h ^-1 .

At the completion of the base synthesis reaction, the recovered product is separated by any possible means
The desired components are separated, for example by fractionation, and the product containing pyridine and / or one or more picoline compounds is recovered. Of the picoline compounds selectively produced according to the present invention, 3-picoline is an important intermediate in the production of 3-pyridinecarboxylic acid, ie, nicotinic acid, and other pharmaceutical, agricultural and chemical products. The method of the present invention, 3-picoline product was collected, by the recovered 3-picoline is contacted with an oxidizing agent such as KMnO _4, further to adapt to the synthesis of 3-pyridinecarboxylic acid Can be modified.

The process of the present invention provides a substantially reduced production of polyalkylpyridines and / or other higher molecular weight aromatic species compared to conventional processes, while providing a desirable pyridine or picoline product Is increased. This is achieved by contacting the polyalkylpyridine by-product in the secondary reaction with a molecular sieve catalyst. "Polyalkylpyridine by-product" means a pyridine derivative having two or more alkyl groups attached to a ring structure. Such compounds are exemplified by lutidine and collidine. In conventional single-pass reactions, those polyalkylpyridine by-products, like other higher molecular weight aromatic species (such as alkylated polynuclear aromatic structures), can be in amounts up to 20% by weight, or even more. Larger amounts are produced, which makes such a method very inefficient. In contrast, the method of the present invention
It has been found that the production of polyalkylpyridines and higher molecular weight aromatic species is reduced to less than 5% by weight, often to less than 2% by weight, usually to less than 1% by weight.

The secondary reaction converts the polyalkylpyridine or other higher molecular weight aromatic species in the polyalkylpyridine fraction to a secondary product rich in pyridine or picoline products. The conversion conditions for the secondary reaction are generally within the same suitable ranges as those specified above for the base synthesis reaction, but the catalyst and conversion conditions used for the secondary reaction are used for the primary reaction. Either the same or different. Preferably, the secondary reaction is performed in the same reactor using the same catalyst as the base synthesis reaction by recycling some or all of the polyalkylpyridine fraction to the primary reactor.

The catalytic base synthesis reaction and the polyalkylpyridine conversion reaction are carried out on a molecular sieve catalyst. Preferred molecular sieve catalysts are those having an intermediate pore size characterized by a constraint index of 1 to 12. The constraint index and the method for determining it are described in U.S. Pat. No. 4,016,218. Examples of suitable intermediate pore size molecular sieves include ZSM-5 (US Pat. Nos. 3,702,886 and Re. 29,948), ZSM-11 (US Pat. No. 3,709,979), ZSM-12 (US Pat. No. 3,832,449), ZSM-
22 (U.S. Pat.No. 4,556,447), ZSM-23 (U.S. Pat.No. 4,076,842), ZSM-35 (U.S. Pat.No. 4,016,245), ZSM-48 (U.S. Pat.No. 4,397,827), ZSM-57 (U.S. Pat. No.) and ZSM-58 (U.S. Pat. No. 4,417,780).

Other useful catalytic materials include MCM-22 (US Pat. No. 4,954,325), MCM-36 (US Pat. No. 5,250,277), MCM-49 (US Pat. No. 5,236,575) and MCM-56 (US Pat. No. 5,236,575). Patent No. 5,362,697). SAPO-5, SAPO-11, zeolite X, zeolite Y and zeolite beta are also examples of molecular sieve materials that can be used in the present invention.

Naturally occurring clays that can be complexed with molecular sieves include those of the montmorillonite and kaolin classes, which include the subbentonites commonly known as Dixie, McNamee, Georgia and Florida clays. ) And kaolins, or other clays whose main mineral constituent is halosite, kaolinite, dickite, nacrite or anauxite. Suitable clay materials include, by way of example, bentonite and diatomaceous earth. Such clays can be used in the unprocessed state as mined or initially subjected to calcination, acid treatment or chemical modification.

The relative proportion of a suitable crystalline molecular sieve to the total composition of catalyst and binder or support is from 1% to 99%, preferably from 30% to 90% by weight of said composition
, More preferably 50% by weight to 80% by weight.

[0026] Hydrogenation-dehydrogenation functional metals can be incorporated into the catalysts of the present invention. The amount of functional metal is suitably from 0.001% to 10%, preferably from 0.05% to 5%, more preferably from 0.1% to 2% by weight, based on the total weight of the modified catalyst. % By weight. Examples of suitable hydrogenation-dehydrogenation metals include Group 8, 9, and 10 metals (ie, Pt, Pd, Ir, Rh, Os, Ru, Ni, Co and Fe), Group 7 metals (ie, Mn, Tc And R
e), Group 6 metals (ie, Cr, Mo and W), Group 15 metals (ie, Sb and Bi),
Includes Group 14 metals (ie, Sn and Pb), Group 13 metals (ie, Ga and In), Group 11 metals (ie, Cu, Ag, and Au) and Group 12 metals (ie, Zn, Cd, and Hg) . Noble metals (ie, Pt, Pd, Ir, Rh, Os, Re, Ru, Mo and W) are preferred.

Example 1 To form a pyridine and picoline product, a base synthesis reaction was carried out using a spray-dried 40% HZDM-5 zeolite in a silica-alumina-clay matrix as a catalyst. In a typical implementation, the 20/40 mesh catalyst 5 to 10ml was placed in a quartz reactor and heated to 440 to 454 ° C. under a N ₂ purge (825 to 850 ° F). The feed comprised acetaldehyde, formaldehyde, ammonia and hydrogen in the following molar ratios. Acetaldehyde = 1.4, formaldehyde = 1.0, ammonia = 3.6, hydrogen = 1.6. The feedstock is passed through catalyze the 580 hour ^-1 GHSV (NH _3), the effluent was analyzed by gas chromatography (GC) using quinoline as an internal standard. The water content in the product was determined by Karl Fischer titration. Table 1 shows the yields of various products of this reaction.

Example 2 The pyridine and picoline products in the effluent of the reaction described in Example 1 were distilled off, collected and the aqueous layer was removed. The heavier N-containing components were recycled back to the reactor. Additional catalyst needed to increase the conversion of polymethylpyridine was added. Table 1 shows the yields of various products after this reaction.

[0029]

[Table 1]

Table 1 shows that the method of the present invention (Example 2) substantially increases the process selectivity for pyridine and picoline as compared to the prior art single-pass method (Example 1). It clearly shows what you can do. The yield of polyalkylpyridine by-product is
Substantially reduced from 18.1% to less than 1%. Note that for comparative purposes, the acetaldehyde conversion in each example was performed by increasing the catalyst charge to the reactor. Thus, the process of the present invention achieves a substantial increase in efficiency based on the total yield of pyridine and picoline products from a given amount of feed.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Han, Scott United States, 08648, New Jersey, Lawrenceville, Valerie Lane 4 North Monroe Ave 10 (72) Inventor Bencat, Chia Lao, New Jersey, USA 08540, Princeton, Literbrook Road North 35 F-term (reference) 4C055 AA01 BA01 BA02 BA03 BA06 CA01 CA02 CA03 CA06 DA01 DA06 FA23 FA24 FA34 FA36

Claims (8)

[Claims] 1. A reaction of a reactant feed stream comprising (a) ammonia and at least one _C1-5 carbonyl reactant in the presence of a molecular sieve catalyst, comprising a pyridine or picoline product and polyalkylpyridines. Producing a primary product stream; (b) isolating from the primary product stream a product fraction containing a pyridine or picoline product and a polyalkylpyridine fraction containing polyalkylpyridines; c) contacting the polyalkylpyridine fraction with a molecular sieve catalyst to produce a pyridine or picoline product-containing secondary product stream. 2. The conditions of steps (a) and (b) include a temperature of 285 to 600 ° C., a pressure of 20 to 2,000 kPa (0.2 to 20 atm) and a GHSV of 200 to 20,000 h ⁻¹ , respectively. The method of claim 1. 3. The conditions of steps (a) and (b) include a temperature of 340 to 550 ° C., a pressure of 80 to 1,000 kPa (0.8 to 10 atm) and a GHSV of 300 to 5,000 h− ¹ , respectively. The method of claim 1. 4. The method according to claim 1, wherein the molecular sieve is ZSM-5, ZSM-11, ZSM12, ZSM-22, ZSM-23, ZSM-35.
, ZSM-48, ZSM-57, ZSM-58, MCM-22, MCM-36, MCM-49, MCM-56, SAPO-5, SAPO-1
1. The method according to claim 1, wherein the method is selected from zeolite beta, zeolite X and zeolite Y. 5. The method of claim 1, wherein the molar ratio of ammonia to at least one carbonyl reactant in the reactant feed stream is from 0.5 to 10. 6. The method of claim 1, wherein the at least one carbonyl reactant comprises acetaldehyde and formaldehyde. 7. The method of claim 1, further comprising supplying hydrogen with the reactant feed stream. 8. The conversion step (c) comprises recycling the polyalkylpyridine fraction to the catalyst used in the reaction step (a), wherein the conversion is carried out in the reaction step (a).
The method according to claim 1, which is carried out under the synthesis reaction conditions.